Amino Acids and Proteins

Question 1

What is the role of fibrous proteins?

Answer 1

Mechanical support

Question 2

Give an example of a fibrous protein

Answer 2

alpha-Keratin

Question 3

What is the role of globular proteins?

Answer 3

Enzymes
Receptors
Water soluble and compact

Question 4

Name some functions of protein

Answer 4

Catalysis
Transport
Structure
Motility
Receptor
Signalling
Immunity
Regulation

Question 5

What drives the folding of globular proteins?

Answer 5

The hydrophobic effect

Hydrophobic amino aids are made into a core, leading a hydrophilic surface

Question 6

Describe the structure of an amino acid

Answer 6

R group
Central carbon
Amino group
Hydrogen
Carboxyl group

Question 7

Name the non polar amino acids

Answer 7

Glycine
Alanine
Proline
Valine
Leucine
Isoleucine

Question 8

Name the aromatic amino acids

Answer 8

Phenylalanine
Tyrosine
Tryptophan

Question 9

Name the polar amino acids

Answer 9

Asparagine
Glutamine
Serine
Threonine

Question 10

Name the sulphur containing amino acids

Answer 10

Methionine

Cysteine

Question 11

Name the negatively charged amino acids

Answer 11

Aspartate

Glutamate

Question 12

Name the positively charged amino acids

Answer 12

Arginine
Lysine
Histidine

Question 13

Which is the most hydrophobic non polar amino acid?

Answer 13

Glycine is the least hydrophobic
Hydrophobicity increases
Isoleucine is most hydrophobic

Question 14

What bond is formed in extracellular proteins for stability and which amino acids are responsible?

Answer 14

Disulphide bridges
Cysteine
Methionine

Question 15

Are the aromatic amino acids polar or non polar?

Answer 15

Phenylalanine is non polar

Tyrosine and tryptophan are more polar

Question 16

Which amino acids have ionising groups?

Answer 16

Aspartate
Glutamate
Histidine
Arginine
Lysine
Tyrosine
Cysteine

Question 17

Which amino acids influence protein structure and function?

Answer 17

The 7 amino acids with ionising groups

Question 18

What are the four levels of protein structure?

Answer 18

Primary
Secondary
Tertiary
Quaternary

Question 19

What is primary structure?

Answer 19

Linear sequence of amino acid residues in a polypeptide

Question 20

What is secondary structure?

Answer 20

Regularly repeating regions of the polypeptides maintained by hydrogen bonding between the peptide groups

Question 21

What is tertiary structure?

Answer 21

The 3D structure of a polypeptide

Question 22

What is the quaternary structure?

Answer 22

Arrangement of more than 1 polypeptide in a multi subunit oligomeric protein

Question 23

How does a peptide bond form?

Answer 23

The carboxyl group and amine group of different amino acids come together and a water molecule is lost

Question 24

What determines the properties of any peptide or protein?

Answer 24

Side chains

Question 25

What is the correct way to write the sequence of a polypeptide?

Answer 25

From the N-terminus to C-terminus

Question 26

What are the two possible secondary structures?

Answer 26

Alpha helix

Beta pleated sheet

Question 27

Describe the bonds in an alpha helix

Answer 27

Each C=O is hydrogen bonded to the amide hydrogen of the amino acid four places ahead

Question 28

Describe collagen

Answer 28

Collagen unit is a triple helix called a tropocollagen molecule This is held together by hydrogen bonds
There are multiple repeats of Gly-X-Y(X= proline, Y=4-hydroxyproline)

Question 29

What is an isozyme?

Answer 29

A tissue-specific physically distinct form of a given enzyme